Spectrum Controls InView Series User Manual page 74

4-10 Chapter 4: InView Protocol
Modbus Holding
Registers
4001
....
40100
40101
400102
400103
...
400167
Function Function
Code Code Hex
01 01
03 03
06 06
User's Manual 0300277-02 Rev. D
•
Format: Number of bits per character - 1 start bit, 7 data, 1 (optional)
parity bit, 1 or 2 stop bits.
For the products, the data communication rate and format is 9600 baud
(maximum), 1 start bit, 7 data bits, even parity, 2 stop bits.
InView Display Memory Map
Information transmitted to the displays writes or reads information into holding
registers. The holding registers used in the products are 40001 to 40167. Holding
registers 40001 to 40103 can be written to. Registers 40001 to 40100, and 40103
to 40167 can be read from.
The product has three basic areas for registers, 100 registers for variables, 3
registers for message control, and 64 registers for the message queue. When
referencing a holding register, Modbus ASCII requires that 40001 be subtracted
from the holding register address.
For example, when using priority messaging, messages are sent to holding
register 40103. The register number that is transmitted would be (40103-
40001=102) or 102 (0×66) would be transmitted at 100 (64h). The following
shows the memory map for the displays.
Memory Map
Registers
001
100
101
102
103
167
Methods of Transmission
There are eight different methods of transmission of data to and from the display.
Each one of these uses 1 of 4 different Modbus function codes.
The table, Modbus Function Codes used in InView Products, explains each of the
four Modbus ASCII function codes used. The table, Methods of Transportation,
shows the eight methods of using these codes with the product.
Modbus Function Codes Used in InView Products
Modbus Meaning
Read Coil Status
Read Output
Registers Query
Preset Single
Register
Description
Variables Registers
Variables 001-100 (00-99 with automation
software
Add a Message/Downloading of messages
Remove a Message
Message Queue/Priority Messaging
Action
Used to signal the downloading of
messages to the display.
Used to read registers in a display.
Used to preset a single register in a
display (Priority Messaging, Update
Variables, and Add/Remove a Message).